http://archive.thenewsstar.com/VideoNetwork/1713050337001/Extreme-Heat-Hits-the-UShttp://cdn.newslook.com/9d/9d933e6d770283dc3ffc07cdf6624689/mp4_low/9d933e6d770283dc3ffc07cdf6624689-mp4_low.mp4http://archive.thenewsstar.com/VideoNetwork/1713050337001/Extreme-Heat-Hits-the-UShttp://cdn.newslook.com/9d/9d933e6d770283dc3ffc07cdf6624689/images/frame_0005.jpgExtreme Heat Hits the USIn Washington, D.C., residents and tourists sought some relief from the heat in fountains and on the Potomac River, as a third of the United States was under a heat advisory. Sarah Irwin reports.24United StatesWashingtonnationalTRIGPnewslookusThomson Reuters Group LtdNewsdomesticD.C.01:05